基于Hopkinson技术的CMDB推进剂动态起裂韧性实验

为了研究改性双基（CMDB）推进剂的动态起裂韧性，利用Hopkinson实验技术对CMDB推进剂的含切缝半圆形（NSCB）试件进行了冲击实验.运用脉冲整形技术，获得了CMDB推进剂的载荷-位移曲线.采用改进型柔度变化率法得到NSCB推进剂试件的起裂点.通过ABAQUS有限元软件对NSCB试件的无量纲结构因子进行了标定，并获得了NSCB的动态起裂韧性.利用电镜扫描设备分析了NSCB试件断裂的微观机理，研究结果表明:在加载率为5.41×105~8.94×105MPa·m1/2·s-1范围内，CMDB推进剂的动态起裂韧性具有显著的加载率敏感性.结合电镜扫描图分析，随着加载率的增大，断面内部颗粒微观结构的破坏形貌逐渐恶化，消耗的能量相应增大. 

Experiment on dynamic fracture initiation toughness of CMDB propellant based on Hopkinson technology

To obtain the dynamic fracture initiation toughness of composite modified double-base (CMDB) propellant, impact experiments of notched semi-circular bend (NSCB) specimens were performed by Hopkinson experimental technology. Pulse shaping technology was applied to obtain the load-displacement curve of CMDB propellant. The modified compliance changing rate method was used to determine the crack initiation point of the NSCB specimen. Finite element software ABAQUS was adopted to calculate the dimensionless structure factor of the NSCB specimen, and the dynamic fracture initiation toughness of the CMDB propellant was determined. The scanning electron microscope imaging technique was used to investigate the fracture micro-mechanisms of the NSCB specimen. Research results show that the dynamic fracture initiation toughness is dependent on the loading rate sensitivity significantly within the range of 5.41×10⁵~8.94×10⁵MPa·m^1/2·s^-1. With the increase of the loading rate sensitivity, the failure morphology of the particles in the cross section is gradually deteriorated, and the energy consumption is increased through the analysis of the scanning electron microscope.